This invention relates generally to an improved beverage brewing device which automates many of the steps involved in a beverage brewing operation.
Automatic brewing devices are known in the art but have not overcome many of the problems associated with such devices. For example, U.S. Pat. No. 4,633,771 to Anderl shows an automatic brewing device which incorporates a movable piston to regulate the brewing cycle. The piston as shown in Anderl is axially moved by a rod which is driven by a motor. The rod advances or retreats based on its engagement with a rotating cam disk. A problem arises with the device of Anderl in that the notches in the cam disc are prone to cause improper brewing if they become coated or clogged with foreign matter. Foreign matter is likely to accumulate on the disc because of the environment in which it operates which includes fines and powder from the beverage brewing substance as well as high humidity from the brewing process.
Another problem with the device as shown in Anderl is that it is difficult to keep the brewing chamber clean and to exhaust spent brewing substance. Anderl shows only a single spray head which proves inefficient and is not thorough in flushing spent brewing substance from the brew chamber.
Another automatic brewing device is shown in U.S. Pat. No. 4,694,737 to Wittlinger. The device as shown in Wittlinger is similar in its operation to the device in Anderl but does not provide improvements resolving the problems of Anderl. Rather, the device in Wittlinger shows improvements to the filtering assembly as used in the brew chamber.
Another problem that arises with automatic beverage brewers is that although they are generally automatic they nevertheless require periodic cleaning. Periodic cleanings include removing a filter assembly disposed in a lower portion of the brewing chamber. The filter assembly is used to support a brewing substance for infusion during a brewing cycle and to separate a brewed beverage created during the brewing cycle. A problem is encountered in cleaning prior art filter assemblies when the piston assembly includes a spool having an enlarged head. A lower portion of the spool movably extends through the drain with the enlarged head movably extending through an inlet in a top portion of the brewed chamber. A port used for delivering flush water is positioned underneath the head between the head and a reduced diameter portion of the spool. The lower portion of the spool is surrounded by a filter assembly which has an aperture through which the lower portion of the spool projects. Since the lower portion of the spool has a smaller diameter than the enlarged head, the filter assembly cannot be installed or removed by positioning it over the enlarged head. As such, removal of the filter assembly in these devices typically requires removal of the piston assembly.
Another problem with prior automatic brewing devices is that once the brewing substance becomes saturate during the brewing process it sinks to the bottom of the brewing chamber. As the brewed beverage is drained off of the brewing substance the moist brewing substance may become caked on and plug the openings in the filter material. At the end of the brewing cycle the brewing chamber is flushed, typically with a spray of water, in order to remove the spent brewing substance. However, because the brewing substance may be caked on the filter material in the drained brewing chamber the rinse water spray does not completely flush the spent brewing substance out of the brewing chamber. Instead, a portion of the spent substance remains in the brewing chamber on the filter material. The remaining substance inhibits flow of brewed beverage through the filter material and thereby reduces the efficiency of the brewer. Further, depending on the time between brewing cycles, the brewing substance remaining on the filter material may become rancid and degrade the flavor of the next serving of beverage to be brewed.
Additionally, another problem with current automatic brewing devices is that the mechanism for dispensing a brewing substance into the brew chamber is inaccurate. One way to controllably dispense a brewing substance into the brew chamber by means of an auger in a hopper. The auger is positioned in the bottom of a hopper in an operative association with an opening in the hopper through which the brewing substance is moved. However, such auger arrangements are often inaccurate and tend to dispense too much brewing substance.